Re: [PATCH v3 1/3] mm: document zone device struct page field usage

[Ralph Campbell <rcampbell@nvidia.com>]

On 7/24/19 6:22 PM, Jason Gunthorpe wrote:
> On Wed, Jul 24, 2019 at 04:26:58PM -0700, Ralph Campbell wrote:
>> Struct page for ZONE_DEVICE private pages uses the page->mapping and
>> and page->index fields while the source anonymous pages are migrated to
>> device private memory. This is so rmap_walk() can find the page when
>> migrating the ZONE_DEVICE private page back to system memory.
>> ZONE_DEVICE pmem backed fsdax pages also use the page->mapping and
>> page->index fields when files are mapped into a process address space.
>>
>> Add comments to struct page and remove the unused "_zd_pad_1" field
>> to make this more clear.
>>
>> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
>> Reviewed-by: John Hubbard <jhubbard@nvidia.com>
>> Cc: Matthew Wilcox <willy@infradead.org>
>> Cc: Vlastimil Babka <vbabka@suse.cz>
>> Cc: Christoph Lameter <cl@linux.com>
>> Cc: Dave Hansen <dave.hansen@linux.intel.com>
>> Cc: Jérôme Glisse <jglisse@redhat.com>
>> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
>> Cc: Lai Jiangshan <jiangshanlai@gmail.com>
>> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
>> Cc: Pekka Enberg <penberg@kernel.org>
>> Cc: Randy Dunlap <rdunlap@infradead.org>
>> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
>> Cc: Christoph Hellwig <hch@lst.de>
>> Cc: Jason Gunthorpe <jgg@mellanox.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Linus Torvalds <torvalds@linux-foundation.org>
>>   include/linux/mm_types.h | 11 ++++++++++-
>>   1 file changed, 10 insertions(+), 1 deletion(-)
> 
> Ralph, you marked some of thes patches as mm/hmm, but I feel it is
> best if Andrew takes them through the normal -mm path.
> 
> They don't touch hmm.c or mmu notifiers so I don't forsee conflicts,
> and I don't feel comfortable to review this code.
> 
> Regards,
> Jason
> 

Fine with me. I should have been clear in the cover letter which
tree to target.